Tertiary butyl alcohol, hereafter referred to as TBA, is a four carbon aliphatic alcohol that due to its intrinsic quaternary structure is extremely resistant to biodegradation. Williams et al (1966) showed that the alcohol dehydrogenase of a species of Pseudomonas was ineffective with tertiary alcohols, yet functioned well with linear and secondary structured alcohols. This finding accounted for the inability of several investigators to degrade tertiary alcohols with activated sludges and microbial isolates (Hatfield, 1957; McKinney et al., 1955, Mohanrao et al, 1962). In the treatise on the bacterial genus Pseudomonas by Stanier et al, (1966), 267 stains of Pseudomonas were examined for their biochemical characteristics. None of the strains examined were reportedly able to metabolize tertiary alcohols.
Dias and Alexander (1971) examined the effect of chemical structure on the biodegradabilty of aliphatic acids and alcohols by microorganisms in sewage sludge. These workers found a relationship between substitution and the rate of degradation. Alpha substituted alcohols showed the greatest resistance to biodegradation. Beta substitution was less refractile than alpha but greater than omega substitution. While the usual group substitution was a halogen, the study did succeed in showing that chemical structure was related to biodegradation. It is generally understood, however, that tertiary structured compounds are extremely resistant to biodegradation since the primary carbon is completely methylated.
There remains, therefore, a need to identify bacteria which are capable of degrading TBA and to make these bacteria available for use in wastewater treatment plants required to handle significant concentrations of the compound.